If the church isn't heavily ethnic, it may be a Weird Convert Thing. I can say this, since I'm a convert. It's funny sometimes. One person does something out of the ordinary, and then several more do it, too. At my mostly convert church, at the trisagion, we used to only make three metanias, and then after "with strength," we would just cross ourselves and bow a little. Now, for some odd reason, people are doing four metanias.
I have only seen blessing with the chalice during the great entrance once, with a rather strange, now ex-priest, and a woman who had cancer. I'm not really sure what the point of great entrance blessings is. I view them the same way I view icon veneration after communion. People are about to, or have just received Christ, why venerate/get blessed by an icon or that which is not yet Christ? I don't really get it.